Method and apparatus for coupling multiple power sources to single radiating antenna

ABSTRACT

A single antenna can be used to radiate power from multiple power sources having a wide, composite frequency band. Frequencyrelated pairs of the sources are combined in input hybrid junction devices. The combined outputs thereof are re-combined in successive hybrid junctions. The re-combined outputs are combined a last time in an output hybrid junction to produce a wide band output.

United States Patent [1 1 [111 3,714,661

Kershaw 1 Jan. 30, 1973 [54] METHOD AND APPARATUS FOR 156] ReferencesCited COUPLING MULTIPLE POWER a I SOURCES T0 SINGLE RADIATING UNITEDSTATES PATENTS ANTENNA 3,453,638 7/1969 Hoover ..333/ll Inventor: JosephE. Kershaw, La Mesa, Calif.

The United States of America as represented by the Secretary of the NavyFiled: Jan. 24, 1972 Appl. No.: 219,999

Assignee:

US. Cl. ..343/858, 333/10, 333/11 Int. Cl. ..H0lq 1/50 Field of Search..343/850, 854, 858; 333/11 Primary ExaminerEli Lieberman Att0rneyR. S.Sciascia et al.

A single antenna can be used to radiate power from multiple powersources having a wide, composite frequency band. Frequency-related pairsof the sources are combined in input hybrid junction devices. Thecombined outputs thereof are re-combined in successive hybrid junctions.The re-combined outputs are combined a last time in an output hybridjunction to produce a wide band output.

ABSTRACT 2 Claims, 1 Drawing Figure METHOD AND APPARATUS FOR COUPLINGMULTIPLE POWER SOURCES TO SINGLE RADIATING ANTENNA BACKGROUND OF THEINVENTION SUMMARY OF THE INVENTION A method for combining up to eightsignals for wideband radiation by a single antenna is disclosed. Thesignals are applied in frequency-related pairs to the E and H inputports of hybrid junctions having a frequency band which includes thefrequency of the two particular signals applied thereto. Each of thehybrid junctions combines the two signals applied at its input ports anddivides the combined signals equally at two output ports, one of whichis terminated. The unterminated,

combined outputs from each junction-are applied again infrequency-related pair to another hybrid junction where these twooutputs are in turn combined. The process is used repetitively tocombine up to eight oscillator outputs for radiation by a singleantenna. The final hybrid junction frequency band includes the frequencyrange for each of eight signals. The power sources may be at anyfrequency within the bandwidth of the hybrids and may be at any phasewith respect to each other.

OBJECTS OF THE INVENTION It is a primary object of the inventive conceptto be disclosed herein to disclose a method using hybrid junctiondevices for combining multiple power sources for radiation by a singleantenna over a wide frequency band.

It is another object of the present invention to dis close a noveltechnique using hybrid junctions whereby a plurality of differentfrequency power sources can be combined for radiation by a singleantenna and which is especially advantageous in the limited spaceenvironment such as on a naval ship.

Other objects, advantages and novel features of the invention willbecome apparent from the following detailed description of the inventionwhen considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING The drawing is a simplified blockdiagram of the novel power source combination technique using hybridjunction devices to be disclosed herein.

DESCRIPTION OF THE PREFERRED EMBODIMENT The inventive concept whichrelates to RF circuitry and which is to be disclosed herein is bestillustrated by the simplified block diagram of the FIGURE. In theFIGURE, eight different power sources P P P P,,, P P P and P havingdifferent frequencies f1, f2, f3, f4, f5, f6, f7 and f8, respectively,are shown being applied in consecutive, frequency-related pairs to theinput hybrid junctions 10, l2, l4, and 16, respectively, at the E and Hports thereof.

The two signals or signal pair applied to each different hybrid junctioneach have a different frequency within the frequency range of thecorresponding hybrid junction. Thus the frequency range of atransmitting system using the concept disclosed herein can encompass thefrequency range f1-f8 covered by the individual power sources.

The output of each power source or oscillator can be connected to theinput port of its associated hybrid junction by attenuator means (notshown). If used, the attenuators are located between the oscillatoroutputs and the input ports to increase the isolation between theoscillators by providing improved terminations for the hybrids and alsoby providing a direct increase in isolation equal to the value of theattenuators.

Each hybrid junction produces two outputs at the output ports which aredesignated in the art as ports I and 2. As can be seen, each of theoutput ports 2 are terminated in a suitable impedance. The output signalat each of the input hybrid junctions output port 1 is proportional tothe sum of the two input signals. The combined signal outputs from thetwo input hybrid junctions wand 12 are coupled to the E and H ports of asucceeding junction 20 having a frequency band which includes thefrequencies fl, f2, f3, and f4.

Again attenuators can be used between the output ports of the inputports of the successive hybrid junction 20 for the reasons given above.Likewise, the output port 2 of the hybrid junction 20 is terminated at18 and at the other output port 1, the output signal is proportional tothe four signals applied to the first two input hybridjunctions l0 and12.

The same technique or method is used with respect to the two otherhybrid junctions l4 and 16 to combine the power sources P P P and P Theoutput of the succeeding hybrid junction 22 is thus an output signalwhich is proportional to the combination of the power sources P, P P,and P Finally, the outputs of the two successive hybrid junctions 20 and22 are coupled to the E and H ports of an output hybrid junction 24whose frequency band must include the frequencies f1, f2, f3, f4, f5,f6, f7, and f8. The unterminated output at the port 1 of the outputhybrid coupler 24 represents a combination of the aforementioned eightinput signals or power sources and since each coupler or junctiondivides the input power equally at its two output ports it can readilybe shown that the output signal of the junction 24 has a magnitudesubstantially equal to any one of the power sources if they are of equalmagnitude, but the output signal obviously has a frequency band equal tofl f8. Thus the output of the output hybrid coupler 24 can be connectedusing conventional RF techniques to a common antenna 26 for radiation ofthe power sources over a wide frequency band.

The hybrid junctions shown in the triangular networ in the FIGUREcomprise well-known, four-port networks capable of splitting inputsignals into equal amplitude, isolated outputs which are either in phaseor out of phase by 180. These networks are known in the microwavecommunity under such names as Magic Tees, Rat Race Hybrids, RingHybrids, and Hybrid Tees, sum and difference hybrid, balanced hybrid,symmetric hybrid, and comparator hybrid.

Operationally, signals fed-to the H, or symmetric port, will splitequally and in phase between the colinear output ports 1 and 2.Likewise, signals fed to the E, or anti-symmetric port, will also splitequally between ports 1 and 2 but will be 180 out of phase. Thisin-phase and out-of-phase relationship results in isolation between theE and H ports. Simultaneous application of signals to both H and E portsresults in the vector thereof addition at one colinear port and vectorsubtraction thereof at the other. Commercially available hybridjunctions cover the various frequency ranges between audio and X bandand perform over an octave or more of bandwidth.

According to the method described above, each hybrid combines thesignals provided at the input ports and divides the input power equallybetween ports E and H. Neglecting losses, the power P, at frequency f1applied on a single coaxial line at a hybrid junction 10 input port Eand the power P at frequency f2 applied at the input port H produces anoutput of k P, h P, watts at the output port 1 and A: P, and r5 P wattsat the terminated port 2.

As shown in the FIGURE, the process can be used repetitively to combineup to eight oscillator outputs for radiation by a single antenna.Obviously eight other signals could be combined in the same manner adifferent number of times and the process repeated with the combinedoutput signals thus obtained.

Thus it can be seen that a novel method for combining multiple powersources for radiation by a single antenna has been disclosed. The methodpermits a single antenna to be used over a wide frequency bandencompassing the frequency range of the several power sources. The powersources to be combined may be fed .at any frequency within the bandwidthof the associated hybrid and may be at any phase with respect to any ofthe other power sources. It is only necessary that each'power source besetto a frequency within the frequency band of the associated hybridcoupler.

The method disclosed herein is especially advantageous for use inlimited space environments since only one antenna to transmit over awide band. Furthermore, it is not necessary to retune a combiningnetwork as in the prior art, lengthy times for frequency shifting areeliminated, and for wideband power amplifiers are not required.Obviously there is also a cost advantage over the prior art.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. it is therefore to beunderstood that within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A method for combining four pairs of power sources having differentfrequencies for radiation by a single antenna comprising the steps of:

combining each of said pairs in a different one of 5 four input hybridjunctions to produce at the outut of each one thereof an output signalsubstanially equal to one-half the power the applied pair;

combining said output signal from each of said four input hybridjunctions in pairs in two succeeding hybrid junctions to produce at theoutputs thereof two re-combined output signals substantially equal toone-half the power of the applied pair;

combining said two re-combined output signals in a final hybrid junctionto produce a final output signal substantially equal to one-half thepower of said two re-combined output signals; and, coupling said finaloutput signal to common antenna means for radiation thereof over afrequency band which includes the frequency of each of said powersources.

2. A hybrid junction network for combining power sources P,, P P P P P Pand P,,, at frequencies fl, f2, f3, f4, f5, f6, f7, and f8,respectively, for radiation by a single antenna over the frequency bandflf8, comprising:

first, second, third and fourth input hybrid junctions having frequencybands which include the frequencies fl and f2, f3 and f4, f5 and f6, andt7 and f8, respectively;

means for coupling P, and P P and P P and P and P and P to the E and Hports of said first, second, third, and fourth input hybrid junctions,respectively;

impedance means connected to one of the two output ports of each of saidinput hybrid junctions; fifth and sixth successive hybrid junctionshaving frequency bands which include the frequencies fl, f2, f3 and f4,and f5, f6, f7, and f8, respectively; means for coupling the output fromsaid first and second input hybrid junctions to the E and H ports ofsaid fifth successive hybrid junction and for coupling the output fromsaid third and fourth input hybrid junctions to the E and H ports ofsaid sixth successive hybrid junction;

impedance means connected to one of the two output ports of each of saidsuccessive hybrid junctions; a seventh output hybrid junction having afrequency band which includes the frequencies f1, f2, f3, f4, f5, f6,f7, and f8,

means for coupling the output from. said fifth and sixth successivehybrid junctions to the E and H ports of said seventh output hybridjunction; impedance means connected to one of the two output ports ofsaid output hybrid junction; and, means for coupling the output of saidoutput hybrid junction to a common antenna.

1. A method for combining four pairs of power sources having differentfrequencies for radiation by a single antenna comprising the steps of:combining each of said pairs in a different one of four input hybridjunctions to produce at the output of each one thereof an output signalsubstantially equal to one-half the power of the applied pair; combiningsaid output signal from each of said four input hybrid junctions inpairs in two succeeding hybrid junctions to produce at the outputsthereof two re-combined output signals substantially equal to one-halfthe power of the applied pair; combining said two re-combined outputsignals in a final hybrid junction to produce a final output signalsubstantially equal to one-half the power of said two re-combined outputsignals; and, coupling said final output signal to common antenna meansfor radiation thereof over a frequency band which includes the frequencyof each of said power sources.
 1. A method for combining four pairs ofpower sources having different frequencies for radiation by a singleantenna comprising the steps of: combining each of said pairs in adifferent one of four input hybrid junctions to produce at the output ofeach one thereof an output signal substantially equal to one-half thepower of the applied pair; combining said output signal from each ofsaid four input hybrid junctions in pairs in two succeeding hybridjunctions to produce at the outputs thereof two re-combined outputsignals substantially equal to one-half the power of the applied pair;combining said two re-combined output signals in a final hybrid junctionto produce a final output signal substantially equal to one-half thepower of said two re-combined output signals; and, coupling said finaloutput signal to common antenna means for radiation thereof over afrequency band which includes the frequency of each of said powersources.